Electric shaver

ABSTRACT

In an electric shaver, the cutting blade is mounted between a pair of piezoelectric elements arranged in opposed polarity in order to impart a sawing movement to the cutting surface of the blade.

United States Patent Harold W. Scott [54] ELECTRIC SHAVER 2 Claims, 5 Drawing Figs.

[52] US. Cl 30/45, 3 l0/8.7 [51] Int. Cl .0 B26b21/00, HOlv 7/00 [50] Field of Search 30/42, 44, 45; 3 l0/8.7

[56] References Cited UNITED STATES PATENTS 3,509,626 5/ 1970 Mead 30/45 1,158,741 [1/1915 Steams 30/45 Primary ExaminerAndrew R. .luhasz Assistant Examiner-Gary L. Smith Att0rneyCurtis, Morris & Safford ABSTRACT: In an electric shaver, the cutting blade is mounted between a pair of piezoelectric elements arranged in opposed polarity in order to impart a sawing movement to the cutting surface of the blade.

ELECTRIC SHAVER BACKGROUND OF THE INVENTION This invention relates to an electric shaver or razor and, more particularly, to a shaver wherein the driving force is a transducer arrangement which includes a pair of piezoelectric crystals arranged in opposed polarity to cause a cutting blade to oscillate in a sawing movement.

The standard electric razor which has been used heretofore consists of an oscillating means for moving a number of blades back and forth across a comb to shear hairs which are brought into cutting relationship by a series of openings in the comb.

Such prior electric razors have generally required carefully machined and sharpened blades which were expensive to replace. Use of such razors results in stubble" hairs due to the head shearing action and the fact that the cutting blade does not rest directly on the surface being shaved.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved electric shaver which may be utilized with a replaceable blade at low cost; and a further object is to provide a shaver which does not require a comb to capture the hairs for shearing and, therefore, results in a smoother shave.

To accomplish these objectives, a cutting blade is mounted on a piezoelectric oscillating mechanism set in a housing. The oscillating mechanism is caused to move in a reciprocating sawing motion so that the blade may nibble away at the hairs to be shaved. Due to the fact that a small amount of the hair is nibbled or sawed away with each movement of the cutting blade, it is possible to use a blade of less sharpness than would normally be needed if the full thickness of a hair were to be cut with a single motion. In addition, since the cutting is by a sawing movement and not by shearing there is less likelihood that hairs will be pulled from the skin irritating the user.

The pair of piezoelectric elements are arranged in opposed polarity so that as one is caused to expand by an applied alternating current voltage and the other will be contracted. This results in a bar carried between the elements being driven rapidly back and fourth so that a cutting blade mounted thereon will have a sawing movement.

BRIEF DESCRIPTION OF THE DRAWINGS In the Drawings:

FIG. l is a side sectional view of a shaver in accordance with the present invention;

FIG. 2 is a sectional view along lines 2-2 of FIG. 1;

FIG. 3 is an enlarged sectional view showing movement of the piezoelectric elements and the blade and mounting during expansion and the contraction of the elements;

FIG. 4 is a fragmentary top view showing a serrated edge on the cutting blade; and

FIG. 5 is a simple circuit diagram showing the electrical connection for the piezoelectric elements.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT Referring to the drawings and to FIGS. 1, 2 and 3 in particular, an electric shaver 10 in accordance with the present in vention is shown. The shaver 10 consists of a housing 12 which may advantageously be molded from a plastic material such as impact-resistant polystyrene. A cutting blade 14 is carried by a blade mounting 16 which is contained in the housing 12. The blade mounting 16 includes a frame member 18 which is ad vantageously made from a nonconductive material. Placed within the frame 18 is a support bar 20 and at each end thereof piezoelectric elements 22 and 24.

Piezoelectric elements are well known in the art and may occur naturally or as synthetic materials. When an electrical potential is placed across the piezoelectric material its length may be extended causing it to exert a force on anything that tries to keep it from changing its length. When the electrical potential is reversed by changing the polarity of the current the elongated material will be reduced in length. Advantageously, if piezoelectric elements 22 and 24 are selected from materials having the same properties but arranged in opposed polarities, one element will lengthen and one will shorten as an alternating current driving voltage is applied.

The frame 18 consists of a base member 25 and end walls 26 and 28. The piezoelectric elements are placed one against each end wall and the support bar 20 is fitted therebetween. The support bar 20 may be adhered to the piezoelectric elements by any suitable means such as an epoxy so that there is a composite unit made from the elements 22 and 24 and the support bar 20.

The frame 18 is set into the housing 12 and rests on shoulders 30. In addition it is kept from vibrating by means of side abutrnents 32.

Extending from the support bar 20 are short stub posts 34. The cutting blade 14 is mounted on the support 20 by openings provided therein which match with the location of the stub posts 34.

The cutting edge 36 of the blade 14 is held back from the skin of the user by means of a skin guard 38. The skin guard 38 permits the shaver 10 to be pressed against the skin but it holds the cutting edge 32 back a sufficient amount to prevent cutting the skin. The closeness of a shave may be increased by moving the cutting edge 36 outwardly towards the edge of the skin guard 38. This adjustment may be made by a simple screw member 39 which is mounted on the housing 12. To hold the blade 14 in place a cover piece 40 is provided. The cover piece 40 may be swingably mounted and held in position by a lock screw 42.

A positive pole lead 44 is connected to piezoelectric elements 22 and 24 and a negative lead 46 is also connected to the elements. However, it will be noted that the polarity is reversed so that when element 22 is being lengthened, element 24 will be shortened, and vice versa. The leads 44 and 46 are lead through the housing 12 and out an opening 48 which may be fitted with a packing ring 50 of any suitable deformable material such as rubber. The leads are connected to an ultrasonic generator 52 which in turn is connected to a source of electrical energy.

The ultrasonic generator 52 may be of any of the various well-known types such as a simple vacuum tube generator or it may utilize solid-state devices.

As shown in FIG. 3, when element 24 is lengthened, element 22 is shortened the same extent. This causes the support bar to move towards the end wall 26 carrying the blade 14 with it. As the voltage is reversed the opposite occurs, moving the blade towards wall 28. Thus as this is repeated the blade moves back and forth nibbling away at the hairs presented to it in much the fashion of a two-man crosscut saw.

In FIG. 4, a serrated edge 36 is shown. This edge may be obtained with limited grinding making the cost of such a blade very small. As a result the blade may be of low cost and, thus, ideal for disposal after a few shaves. Of course, a more finely sharpened blade may be used if desired.

It will be noted that in the embodiment illustrated in FIGS. 2 and 3 electrical insulators 56 are placed between the piezoelectric elements 22 and 24 and the support bar 20. Of course, if the bar 20 is made of nonconductive material the insulators are not necessary.

In FIG. 5, a simple electrical circuit is shown which may be used for the illustrated piezoelectric elements. It will be noted that in the arrangement the support bar is used as a conductor for the line L2.

It is to be understood that any suitable mounting means may be used for positioning the blade in relationship to the piezoelectric elements which actually impart motion to the blade through the holder.

What is claimed:

1. An electric shaver comprising 1. a housing;

2. a cutting blade;

3. a piezoelectric oscillating mechanism mounted in the housing and adapted to support the cutting blade;

4. said piezoelectric oscillating mechanism including a pair of piezoelectric elements, each fixed on the end portion of a blade support, said elements being arranged in opposite polarity whereby one element is lengthened and the other shortened by an applied alternating current voltage and a sawing movement may be imparted to the 

1. An electric shaver comprising
 1. a housing;
 2. a cutting blade;
 3. a piezoelectric oscillating mechanism mounted in the housing and adapted to support the cutting blade;
 4. said piezoelectric oscillating mechanism including a pair of piezoelectric elements, each fixed on the end portion of a blade support, said elements being arranged in opposite polarity whereby one element is lengthened and the other shortened by an applied alternating current voltage and a sawing movement may be imparted to the blade support and the blade; and
 5. energizing means including a source of electrical energy for oscillating the piezoelectric mechanism.
 2. a cutting blade;
 2. An electric shaver as defined in claim 1 wherein the energizing means further includes an ultrasonic generator.
 3. a piezoelectric oscillating mechanism mounted in the housing and adapted to support the cutting blade;
 4. said piezoelectric oscillating mechanism including a pair of piezoelectric elements, each fixed on the end portion of a blade support, said elements being arranged in opposite polarity whereby one element is lengthened and the other shortened by an applied alternating current voltage and a sawing movement may be imparted to the blade support and the blade; and
 5. energizing means including a source of electrical energy for oscillating the piezoelectric mechanism. 